1. Field of the Invention
The present invention relates to a magnetic recording medium fabrication method.
2. Description of the Related Art
Recently, a magnetic storage apparatus may be provided in various products, including a personal computer, a video recorder, a data server, and the like, and the importance of the magnetic storage apparatus is increasing. The magnetic storage apparatus includes a magnetic recording medium that magnetically stores electronic data by magnetic recording. Examples of the magnetic storage apparatus include a magnetic disk drive, a flexible disk drive, a magnetic tape apparatus, and the like. A HDD (Hard Disk Drive) is an example of the magnetic disk drive.
For example, a general magnetic recording medium has a multi-layer stacked structure including an underlayer, an intermediate layer, a magnetic recording layer, and a protection layer that are deposited in this sequence on a nonmagnetic substrate, and a lubricant layer coated on a surface of the protection layer. In order to prevent mixing of impurities between the layers forming the magnetic recording medium during fabrication of the magnetic recording medium, an in-line vacuum deposition apparatus is used to continuously stack the layers under decompression, as described in Japanese Laid-Open Patent Publication No. 8-274142, for example.
In the in-line vacuum deposition apparatus, a plurality of deposition chambers having a deposition means capable of depositing a layer on the substrate are connected via a gate valve, together with a chamber for carrying out a thermal process and an auxiliary chamber, are provided in order to form a single deposition line. When the substrate is set on a carrier and passes through the deposition line, the layers are successively deposited on the substrate to fabricate the magnetic recording medium having the desired structure.
Generally, the deposition line is arranged in a ring shape, and a substrate loading and unloading chamber is provided in the deposition line in order to load and unload the substrate with respect to the carrier. The carrier, which passes through the deposition chambers of the deposition line, reaches the substrate loading and unloading chamber where the substrate having the layers deposited thereon is unloaded from the carrier. In addition, after removing the substrate from the carrier, a new substrate to be subjected to the deposition is loaded onto the carrier in the substrate loading and unloading chamber.
In addition, as a method of forming the lubricant layer on the surface of the magnetic recording medium, a vapor-phase lubrication has been proposed in Japanese Laid-Open Patent Publication No. 2004-002971, for example. The vapor-phase lubrication places the magnetic recording medium within a vacuum chamber, and introduces gas lubricant into the vacuum chamber.
When fabricating the magnetic recording medium having the multi-layer stacked structure using the in-line vacuum deposition apparatus, the magnetic recording layer is formed by sputtering using the vacuum deposition apparatus, the protection layer is formed by ion-beam deposition using the vacuum deposition apparatus, and the lubricant layer is formed by vapor-phase lubrication using the vacuum deposition apparatus, for example. Hence, the deposition processes from the formation of the magnetic recording layer up to the formation of the lubricant layer may be performed without exposing a stacked body to the atmosphere.
In addition, a magnetic recording medium having a lubricant layer formed by two layers has been proposed in Japanese Laid-Open Patent Publication No. 2006-147012, for example. The lubricant layer of this proposed magnetic recording medium is formed by a fixing layer (or bond layer) that is provided on the side of the protection layer, is chemically stable, and has a suitable bond with respect to the protection layer, and a fluid (or free layer) that is provided on the surface side of the magnetic recording medium and is mainly made of a material having a low coefficient of friction.
When the contact between the magnetic recording medium and the magnetic head is taken into consideration, the coefficient of friction of the lubricant layer is preferably low. On the other hand, when a corrosion resistance of the magnetic recording medium is taken into consideration, a coverage of the surface of the protection layer provided by the lubricant layer is preferably high.